US5148090A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable reluctance type ac servo motor
Assignee: Fanuc Corp
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Filing: 1989-09-28
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Granted: 1992-09-15
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Expires: 2009-09-28
Abstract
Abstract This invention determines the configurations of a rotor (10) and a stator (12) and conductance periods and conductance phases of the conductance currents to obtain a smooth rotation of a variable reluctance motor as an AC servo motor. When the number of phases of a motor is m, the number of salient poles (R j ) of a rotor (10) is an integer n, and the number of salient poles (S k ) of a stator (12 ) is r·m, n is a whole multiple of r, and where the configuration of the stator salient pole (S k ) is rectangular and the configuration of the rotor salient pole (R j ) is sinusoidal, AC sine wave currents shifted by 2nπ/(r·m) each and having two times as large a period as that of a magnetic permeance fluctuation caused by a rotation of the rotor (10), are conducted to the phases of the motor.
Inventors
- 👤 Hideaki Oku
- 👤 Takeshi Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:47
CPC Classifications
H; H02; H02K; H02K19/00; H02K19/02; H02K19/10; H02K19/103
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
197 words
A variable reluctance type AC servo motor comprising: a stator having a plurality of salient poles, each said stator salient pole having a substantially rectangular surface area; a rotor having a plurality of salient poles opposing said stator salient poles, each said rotor salient pole having a surface area opposing said stator salient poles shaped such that, upon rotation of said rotor, the surface area of each rotor salient pole opposing a stator salient pole varies continuously in a sinusoidal manner; and means for applying AC singe wave excitation currents to windings of said stator poles; wherein the number of m of phases of excitation currents is at least 3, the number of poles of said rotor is an integer n and the number of poles of said stator is r·m, n being a whole multiple of the number r but not a whole multiple of r·m; and wherein the m phase currents have a period Hz equal to twice a period of fluctuation of magnetic permeance caused by rotation of the rotor, and a conductance phase between adjoining stator poles is shifted 2n π/(r·m) at each phase of magnetic permeance fluctuation, whereby torque ripple is eliminated.
Claim 2
Dependent Claim
197 words
A variable reluctance type AC servo motor comprising: a stator having a plurality of salient poles, each said stator salient pole having a substantially rectangular surface area; a rotor having a plurality of salient poles opposing said stator salient poles, each said rotor salient pole having a surface area opposing said stator salient poles shaped such that, upon rotation of said rotor, the surface area of each rotor salient pole opposing a stator salient pole varies continuously in a sinusoidal manner; and means for applying AC singe wave excitation currents to windings of said stator poles; wherein the number of m of phases of excitation currents is at least 3, the number of poles of said rotor is an integer n and the number of poles of said stator is r·m, n being a whole multiple of the number r but not a whole multiple of r·m; and wherein the m phase currents have a period Hz equal to twice a period of fluctuation of magnetic permeance caused by rotation of the rotor, and a conductance phase between adjoining stator poles is shifted 2n π/(r·m) at each phase of magnetic permeance fluctuation, whereby torque ripple is eliminated.
Claim 3
Dependent Claim
73 words
A variable reluctance type AC servo motor according to claim 1, wherein the number n of said rotor salient poles is equal to at least the number m of phases, sinusoidal variation of surface area of a rotor salient pole opposing the stator salient pole has a pitch dimension RP in a circumferential direction of said rotor, and each stator salient pole has a dimension in a circumferential direction equal to RP 2.
Claim 4
Dependent Claim
91 words
A variable reluctance type AC servo motor according to claim 1, wherein said rotor is constructed of a plurality of superposed identical plate members, each of which plate members is formed with a number n of angularly equi-spaced projecting portions of equal width in a circumferential direction, and wherein adjacent said plate members are skewed with respect to each other in a longitudinal direction said rotor such that said projecting portions form said rotor salient poles wherein a surface area opposing each stator salient pole varies sinusoidally as said rotor rotates.
Claim 5
Dependent Claim
90 words
A variable reluctance type AC servo motor according to claim 2, wherein said rotor is constructed of a plurality of superposed identical plate members, each of which plate members is formed with a number n of angularly equi-spaced projecting portions of equal width in the circumferential direction, and wherein adjacent plate members are skewed with respect to each other in a longitudinal direction of said rotor such that said projecting portions form said rotor salient poles wherein a surface area opposing each stator salient varies sinuosidally as said rotor rotates.
Claim 6
Dependent Claim
25 words
A variable reluctance type AC servo motor according to claim 3, wherein said motor includes a plurality of said rotors arranged longitudinally of said rotor.
Claim 7
Dependent Claim
25 words
A variable reluctance type AC servo motor according to claim 4, wherein said motor includes a plurality of said rotors arranged longitudinally of said motor.
References Cited (Backward Citations)
US3956678A
Cited
JPS5037014A
Cited
US4506182A
Cited
US4573003A
Cited
US4670696A
Cited
US4698537A
Cited
US4883999A
Cited
US4896088A
Cited
US4933620A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1995-09-15 | 1996-03-16 | 1996-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-15 | 2000-03-16 | 2000-09-15 | $3760.00 | Window Closed / Lapsed |
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